Light sources such as incandescent and fluorescent sources are increasingly being replaced by light emitting diode sources (hereafter, LED or LEDs). In many instances an LED light source includes a plurality of LED packages, wherein each package includes one or more LED chips. The LED package may include a plastic body that surrounds a lead frame that is configured to allow electrical connections to the LED chip(s). The body may be configured such that a volume remains above the LED chip. In some instances that volume may be filled with a wavelength conversion material (e.g., a phosphor) or another material that may affect the wavelength or other characteristics of the light emitted from the LED chip.
In many instances, LED packages are mounted on a circuit substrate that is made of relatively stiff material such as fiber reinforced epoxy (e.g., FR4) or polyimide. The circuit substrate is generally processed to bear conductive traces and/or other components of a printed circuit on a surface thereof. LED packages may be mounted or otherwise coupled to the traces to produce a lighting array. Although such lighting arrays are useful, the use of relatively stiff circuit substrates may impose design limitations. Technology has therefore been developed to permit the use of circuit substrates that are manufactured from flexible materials such as plastics.
In many instances, a conductive epoxy or other adhesive may be used to adhere the LED package to the substrate and maintain electrical contact between the LED package and traces on the substrate. While this approach is useful in low stress applications, flexion of the substrate may cause the adhesive to crack, potentially compromising the electrical connection between the LED package and corresponding electrical traces. Accordingly, there remains in need in the art for improved technologies for securing LED packages to flexible substrates.
Furthermore while packaging LED chips into an LED package is well established, the cost of packaging can greatly increase the cost of final products into which the LED packages are incorporated. It would therefore be an advance in the art if the need to package LED chips could be eliminated. Simplified placement of LED packages and/or LED chips on flexible substrates may also be desired.